In the context of cryptography, consensus algorithms are a key element of any blockchain network because they are responsible for maintaining the integrity and security of these distributed systems. The first cryptocurrency consensus algorithm that was developed was Proof of Work (PoW), which was designed by Satoshi Nakamoto and implemented on Bitcoin as a way to overcome Byzantine errors.

The consensus algorithm can be defined as the mechanism by which the blockchain network reaches a consensus (it agrees without any doubt on a particular issue). Public (decentralized) block chains are built as distributed systems, and since they do not rely on a central authority, the distributed nodes must agree on the validity of the transaction. This is where consensus algorithms come into play. They ensure that the rules of protocol are followed and guarantee that all transactions take place in an untrusted manner, so coins can be issued only once.

Explain a consensus algorithm